In general, a high-voltage electricity receiving utility contracts with a power company and pays the electricity charges by setting a mean power for 30 minutes that electric power has been used the most in past one year as a contract demand (see Non-Patent Literature 1 and Non-Patent Literature 2). Therefore, it becomes important to suppress a demand value (a maximum demand power) in order to save the electricity charges.
In order to suppress this demand value, a demand controller has been widely used. This demand controller is a device for monitoring ever changing electric power used of the receiving entity and controlling a load system so as not to exceed a fixed value when it is estimated to exceed a set demand value.
For example, a system that automatically changes a set value of the demand controller is disclosed in Patent Literature 1.
In addition, a demand control system that selects an air conditioner to be stopped on the basis of order data of air conditioners is disclosed in Patent Literature 2.
In addition, air-conditioning control controllers capable of performing demand control are introduced in Non-Patent Literature 3 and Non-Patent Literature 4.